Wireless communication apparatus

ABSTRACT

A wireless communication apparatus includes a first housing, a second housing which is openably and closably connected to the first housing through a hinge, a first conductor part which is arranged on the first housing, a second conductor and an antenna element, which are arranged on the second housing and an antenna switching part that makes the first conductor part, the second conductor part, and the antenna element serve as a dipole antenna when the first housing and the second housing are in an open state, and makes the antenna element serve as a monopole antenna when the first conductor and the second conductor are in a closed state.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority of theprior Japanese Patent Application No. 2010-150530, filed on Jun. 30,2010, the entire contents of which are incorporated herein by reference.

FIELD

The present invention relates to an antenna switching control using aplurality of antenna elements.

BACKGROUND

Arrangement of antenna elements in the respective foldable housing partsof a portable apparatus, such as a mobile terminal, has been known inthe art.

For example, Japanese Laid-open Patent Publication No. 2004-229048discloses that a dipole antenna is constructed of a first antennaelement in one housing part and a conductive antenna in the otherhousing part; and a monopole antenna is constructed of a second antennaelement located near a hinge.

Japanese Laid-open Patent Publication No. 2006-14128 discloses that oneof openable/closable housing parts is provided with first and secondconductive plates. The conductive plates are controlled betweenopen-state and connected-state each other in response to the opening andclosing of the housing parts.

SUMMARY

According to an aspect of the embodiment, a wireless communicationapparatus includes a first housing, a second housing which is openablyand closably connected to the first housing through a hinge, a firstconductor part which is arranged on the first housing, a secondconductor and an antenna element, which are arranged on the secondhousing and an antenna switching part that makes the first conductorpart, the second conductor part, and the antenna element serve as adipole antenna when the first housing and the second housing are in anopen state, and makes the antenna element serve as a monopole antennawhen the first conductor and the second conductor are in a closed state.

The object and advantages of the invention will be realized and attainedby at least the elements, features, and combinations particularlypointed out in the claims.

It is to be understood that both the foregoing general description andthe following detailed description are example and explanatory and arenot restrictive of the invention, as claimed.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram each illustrating an example dipole antenna which isset up when a portable apparatus according to a first embodiment is inan open state;

FIG. 2 is a diagram illustrating an example configuration of a monopoleantenna which is set up when the portable apparatus is in a closedstate;

FIG. 3 is a diagram illustrating an example configuration of a cellphone in an open state according to a second embodiment;

FIG. 4 is a diagram illustrating an example wired power supply linepassing through a hinge of the cell phone;

FIG. 5 is a diagram illustrating an example dipole antenna which is setup when the cell phone is in an open state;

FIG. 6 is a diagram illustrating an example configuration of a monopoleantenna which is set up when the cell phone is in a closed state;

FIG. 7 is a diagram illustrating an example antenna-switching circuitwhen the cell phone is in an open state;

FIG. 8 is a diagram illustrating an example antenna-switching circuitwhen the cell phone is in a closed state;

FIG. 9 is a diagram illustrating an example control logic table of achangeover switch part;

FIG. 10 is a circuit diagram illustrating an example antenna-switchingcircuit and an example matching circuit;

FIG. 11 is a diagram illustrating an example connection structure of aflexible substrate passing through the hinge;

FIG. 12 is a diagram illustrating an example connection structure of aflexible substrate passing through the hinge;

FIG. 13 is a diagram illustrating an example connection structure of aflexible substrate passing through the hinge;

FIG. 14 is a diagram illustrating an example connection structure of aflexible substrate passing through the hinge;

FIG. 15 is a diagram illustrating the radiation characteristics of adipole antenna when the cell phone is in a closed state;

FIG. 16 is a diagram illustrating the radiation characteristics of amonopole antenna when the cell phone is in a closed state;

FIG. 17 is a diagram illustrating an example configuration of an antennawhen a cell phone according to a third embodiment is in an open state;

FIG. 18 is a diagram illustrating an example dipole antenna which is setup when the cell phone is in an open state;

FIG. 19 is a diagram illustrating an example configuration of a monopoleantenna which is set up when the cell phone is in a closed state;

FIG. 20 is a diagram illustrating an example antenna-switching circuitwhen the cell phone is in an open state;

FIG. 21 is a diagram illustrating an example antenna-switching circuitwhen the cell phone is in a closed state;

FIG. 22 is an example configuration of a TV receiver circuit accordingto a fourth embodiment;

FIG. 23 is a diagram illustrating an example configuration of a dipoleantenna which is set up when a cell phone is in an open state;

FIG. 24 is a diagram illustrating an example configuration of a monopoleantenna which is set up when the cell phone is in a closed state;

FIG. 25 is a diagram illustrating a comparative example of an antennawhich is set up when a cell phone is in an open state; and

FIG. 26 is a diagram illustrating a comparative example of an antennawhich is set up when a cell phone is in a closed state.

DESCRIPTION OF EMBODIMENTS

In the case where antenna elements are installed on respective foldablehousing parts and these antenna elements are operated in differentconfigurations depending on the open/closed state of the housing parts,the antenna performance may degrade when usable frequencies are in alower frequency band. In particular, if a reduction in size of theapparatus is desired, the performance of the apparatus may degrade dueto a decrease in antenna length (electric length) with respect to thewavelength used. Furthermore, the installation of an extension board inthe housing to make the antenna length longer may involve an increase inspace in the housing and may lead to disadvantages in reducing the sizeand thickness of the apparatus.

First Embodiment

According to a first embodiment, a portable apparatus is designed to setup a dipole antenna when a housing is opened and to set up a monopoleantenna when the housing is closed.

The first embodiment will be described with reference to FIG. 1 and FIG.2. FIG. 1 illustrates an example dipole antenna which is set up when aportable apparatus is in an open state. FIG. 2 illustrates an examplemonopole antenna which is set up when a portable apparatus is in aclosed state.

This portable apparatus 2 is an example portable apparatus of thepresent disclosure and includes a foldable housing 4. As illustrated inFIG. 1 and FIG. 2, this housing 4 includes a first housing part 6 and asecond housing part 8, which are able to perform an open or closemovement about a hinge 10.

The housing part 6 has a first circuit board 12 and functions as a firstantenna element 14.

The housing part 8 is provided with a second circuit board 16, and asecond antenna element 18 is arranged on the exterior of the secondcircuit board 16. The circuit board 12 is provided with a groundconductor 20 and the circuit board 16 is provided with a groundconductor 22. The ground conductors 20 and 22 are example conductorparts.

The housing part 8 is provided with a power supply point 24 as a powersupply part. The power supply point 24 is connected to the groundconductor 20 of the circuit board 12 through a power supply line 26 andalso connected to the ground conductor 22 of the circuit board 16.

When the housing 4 is in an open state, as illustrated in FIG. 1, oneantenna element part 28A of a dipole antenna 28 serves as a firstantenna element 14 and another antenna element part 28B serves as aground conductor 22 of an antenna element 18. In this case, the antennaelement 18 connected to the ground conductor 22 serves as an extensionelement of the ground conductor 22.

If the housing 4 is in a closed state, as illustrated in FIG. 2, theantenna element 18 is connected to the power supply point 24 through apower supply line 30, thereby forming a monopole antenna 32. In thiscase, the ground conductor 22 of the circuit board 16 is connected tothe ground conductor 20 of the circuit board 12 because the power supplyline 26 is replaced by the power supply line 30.

This configuration causes the housing 4 in open state to form a dipoleantenna 28. In this case, one antenna element part 28B connects theantenna element 18 to the ground conductor 22. Thus, the antenna lengthof the ground conductor 22 is extended by the antenna element 18. As aresult, the antenna characteristics of the dipole antenna 28 degradationmay be reduced or prevented because enhanced antenna characteristics ofthe dipole antenna 28, a reduction of size and thickness of the housing4, and lower usable frequency may be attained.

Furthermore, when the housing 4 is in a closed state, the antennaelement 18 forms a monopole antenna 32. In this case, the antennaelement 18 obtains monopole antenna characteristics without receivingany influence from the cancellation of emission current passing throughthe opposite ground conductors 20 and 22.

Therefore, the dipole antenna 28 is formed in the open state and themonopole antenna 32 is formed in the closed state, so that broadcasting,such as digital broadcasting, may be efficiently received using any ofthese antennas.

Second Embodiment

According to a second embodiment, a portable apparatus is designed todetect the open or closed state of a housing and automatically switchbetween a dipole antenna and a monopole antenna in response to theresult of the detection.

The second embodiment will be described with reference to FIG. 3 andFIG. 4. FIG. 3 is a diagram illustrating an example configuration of aportable apparatus in an open state according to a second embodiment.FIG. 4 is a diagram illustrating an example wired power supply linepassing through a hinge of the portable apparatus. In FIGS. 3 and 4, thesame reference numerals denote substantially the same structuralcomponents as those illustrated in FIG. 1 and FIG. 2.

A cell phone 34 is an example portable apparatus of the presentdisclosure. As illustrated in FIG. 3, a housing 4 is divided into ahousing part 6 and a housing part 8, which are connected to each otherby a hinge 10 to allow them to be opened and closed and to be foldableas described above. The hinge 10 includes a hinge mechanism thatconnects the housing parts 6 and 8 so as to be rotatable about the hingeaxis.

The housing part 6 is a display-side housing on which a circuit board 12is mounted. A ground conductor (GND) 20, a first matching circuit 36,and a connector 38 are mounted on the circuit board 12. The groundconductor 20 forms an antenna element 14 which has been described above.The connector 38 is connected to the ground conductor 20 through thematching circuit 36.

The housing part 8 is, for example, an operation-side housing on which acircuit board 16 and an antenna element 18 are mounted. A flexiblesubstrate (cable) 39 and a power supply line 26A are arranged betweenthe housing part 6 and the housing part 8. The circuit board 16 includesa ground conductor (GND) 22, power supply lines 26B, 26C, 26D, and 26E,a connector 40, changeover switches 42 and 44, matching circuits 46 and48, a wireless unit 50, an open/close sensor 52, and a centralprocessing unit (CPU) 54. The matching circuit 46 corresponds to a thirdmatching circuit and the matching circuit 48 corresponds to a secondmatching circuit.

The ground conductor 20 on the circuit board 12 serves as a firstantenna element 14 and the antenna element 18 serves as a monopoleantenna 32. In other words, the cell phone 34 includes two antennaelements, one is a dipole antenna 28 (FIG. 5), and the other is themonopole antenna 32 (FIG. 6).

The ground conductor 22 is an example conductor part. The antennaelement 18 is placed on the exterior of the circuit board 16 and isprovided as an elongation element of the ground conductor 22 when theantenna element 18 serves as the dipole antenna 28 (FIG. 5).

A flexible substrate 39 is an example connection module, which is wiredaround the hinge 10 and connected to the connectors 38 and 40 asillustrated in FIG. 4. A power supply line 26A is arranged along theflexible substrate 39.

The ground conductor 20 is connected to the wireless unit 50 through thematching circuit 36, the power supply line 26A, the changeover switch42, and the power supply line 26B. The changeover switch 42 is a devicefor switching between the connection of the power supply line 26A to thewireless unit 50 and the connection of the power supply line 26C to thewireless unit 50. The matching circuit 36 is an example device formatching the wireless unit 50 to the ground conductor 20 through thepower supply line 26A, the changeover switch 42, and the power supplyline 26B.

The wireless unit 50 is connected to the antenna element 18 through thematching circuit 46, a power supply line 26D, a changeover switch 44,and a power supply line 26E. The matching circuit 46 is an example of adevice for matching the antenna element 18 and the ground conductor 22to the wireless unit 50. The changeover switch 44 is an example devicefor switching between the connection of the antenna element 18 to thepower supply line 26C and the connection of the antenna element 18 tothe power supply line 26D.

Furthermore, the antenna element 18 is connected to the wireless unit 50through the power supply line 26B, the changeover switch 42, the powersupply line 26C, the matching circuit 48, the changeover switch 44, andthe power supply line 26E. The matching circuit 48 is an example devicefor matching the antenna element 18 to the wireless unit 50 through thepower supply line 26B, the changeover switches 42 and 44, and the powersupply lines 26C and 26E.

Furthermore, the open/close sensor 52 is an example device for detectingopening and closing of the housing 4 and sends a detection signal as aresult of the detection to a CPU 54. The CPU 54 is an example device forcontrolling switching between the changeover switches 42 and 44. Thus,the changeover switches 42 and 44 are connected to the CPU 54 throughthe control line 56.

The opening and closing of the housing 4 and the switching between theantennas will be described with reference to FIG. 5 and FIG. 6. FIG. 5is a diagram illustrating an example dipole antenna which is set up in acell phone in an open state. FIG. 6 is a diagram illustrating an examplemonopole antenna which is set up in a cell phone in an open state. InFIG. 5 and FIG. 6, the same reference numerals denote substantially thesame structural components as those illustrated in FIG. 3.

When the cell phone 34 is in the open state, a dipole antenna 28 (FIG.5) is formed. As illustrated in FIG. 5, the ground conductor 20 of thecircuit board 12 on the housing 6 is connected to the wireless unit 50through the matching circuit 36 and the power supply lines 26A and 26B.In addition, the ground conductor 22 for the antenna element 18, thematching circuit 46, and the circuit board 16 is connected to thewireless unit 50. In other words, the dipole antenna 28 illustrated inFIG. 5 is formed such that the ground conductor 20 is used for oneantenna element part 28A of the dipole antenna 28, and both the groundconductor 22 and the antenna element 18 are used for the other antennaelement part 28B.

In this dipole antenna 28, if I₁ denotes an emission current flowingthrough the ground conductor 20 and I₂ denotes an emission currentflowing through the ground conductor 22, the emission currents I₁ and I₂are in phase with each other.

In addition, when the cell phone 24 is in the closed state, a monopoleantenna 32 (FIG. 6) is formed. As illustrated in FIG. 6, the antennaelement 18 is connected to the wireless unit 50 through the power supplylines 26C and 26E to form a monopole antenna 32.

Since the ground conductors 20 and 22 face each other, the emissioncurrent I₁ flowing through the ground conductor 20 and the emissioncurrent I₂ flowing through the ground conductor 22 are in opposite phaseto cancel each other out. As a result, the antenna element 18 serves asa monopole antenna 32.

Referring now to FIGS. 7, 8, and 9, an antenna switching circuit will bedescribed. FIG. 7 is a diagram illustrating the antenna-switchingcircuit when the housing is in an open state. FIG. 8 is a diagramillustrating the antenna-switching circuit when the housing is in aclosed state. FIG. 9 is a diagram illustrating a control logic table ofa changeover switch.

In an antenna-switching circuit 58, when the open/close sensor 52detects the open state of the housing 4, the CPU 54 generates an output,for example a control output H, for setting up the dipole antenna 28. Asillustrated in FIG. 7, the control output H makes the changeover switch42 switch to OUTA1, while making the changeover switch 44 switch toOUTB1.

At this time, the wireless unit 50 is connected to the first antennaelement 14 through the changeover switch 42 and the matching circuit 36,and also connected to the second antenna 18, the changeover switch 44,the matching circuit 46, and the ground conductor 22. Therefore, thedipole antenna 28 described above is formed and connected to thewireless unit 50.

When the open/close sensor 52 detects the closed state of the housing 4,the CPU 54 generates an output, for example a control output L, forsetting up the monopole antenna 32. As illustrated in FIG. 8, thecontrol output L makes the changeover switch 42 switch to OUTA2, whilemaking the changeover switch 44 switch to OUTB2.

At this time, the wireless unit 50 is connected to the second antennaelement 18 through the changeover switch 44, the matching circuit 48,and the changeover switch 42. Therefore, the monopole antenna 32described above is formed and connected to the wireless unit 50.

As illustrated in FIG. 9, the switching between the antennas asdescribed above employs control logic for the changeover switches 42 and44.

According to the control logic, when the housing 4 is in the open state,the output of the open/close sensor 52 is high (H) and theaforementioned control output H is output to the control line 56. Thus,the connection state of the changeover switch 42 is switched toINA-OUTA1 and the connection state of the changeover switch 44 isswitched to INB-OUTB1. Furthermore, when the housing 4 is in the closedstate, the output of the open/close sensor 52 is low (L) and theaforementioned control output L is output to the control line 56. Thus,the connection state of the changeover switch 42 is switched toINA-OUTA2 and the connection state of the changeover switch 44 isswitched to INB-OUTB2.

Referring now to FIG. 10, an antenna switching circuit will bedescribed. FIG. 10 illustrates an example antenna switching circuit. InFIG. 10, the same reference numerals denote substantially the samestructural components as those illustrated in FIGS. 7 and 8.

The wireless unit 50 is connected to the changeover switch 42 through acoupling capacitor C₁. The matching circuit 36, which is connectedbetween the changeover switch 42 and the first antenna element 14,includes a capacitor C₂. In addition, the matching circuit 48 includesan inductor L₁, which is connected between the changeover switch 42 andthe changeover switch 44 in series, and an inductor L₂ and a capacitorC₃, which are connected in parallel with each other. In addition, thematching circuit 46 includes an inductor L₃ connected between thechangeover switch 44 and the ground controller 22.

Referring now to FIGS. 11 to 14, the connection structure of theflexible substrate 39 arranged on the hinge unit 10 will be described.FIGS. 11 to 14 illustrate an example connection structure of theflexible substrate.

As illustrated in FIG. 11, the connector 38 is arranged on the circuitboard 12 on the housing part 6 and connected to the flexible substrate39. The power supply line 26 is connected to the ground conductor 20 ofthe circuit board 12 and placed on the flexible substrate 39.

For example, the connector 38 connected to the flexible substrate 39 maybe a FPC connector. As illustrated in FIG. 12, the connector 38 is fixedon the circuit board 12 and connected to the circuit wiring of thecircuit board 12. The power supply line 26 is led to the housing part 8through another route different from the route of the flexible substrate39 and connected to the changeover switch 42.

As illustrated in FIGS. 13 and 14, the flexible substrate 39 passingthrough the hinge 10 is led to the circuit board 16 on the housing part8 and connected to the circuit wiring of the circuit board 16. The powersupply line 26 passes through the hinge 10 along the flexible substrate39 and is led to the circuit substrate 16.

The flexible substrate 39 is connected to the circuit board 16 using theconnector 40, such as a stacking connector. The power supply line 26 isconnected to the changeover switch 42 on the wireless unit 50 via aconnection terminal section 60 provided on the stacking connector.

The characteristics of the dipole antenna 28 and the monopole antenna 32will be described with reference to FIGS. 15 and 16. FIG. 15 illustratesthe characteristics of the dipole antenna. FIG. 16 illustrates thecharacteristics of the monopole antenna.

FIG. 15 illustrates the antenna radiation characteristics of the dipoleantenna 28. Thick line “a” represents the characteristics with theconnected antenna element 18 present and thin line “b” represents thecharacteristics with the antenna element 18 absent.

As is evident from the comparison between the characteristicsrepresented by the lines “a” and “b”, the dipole antenna 28 connected tothe antenna element 18 serves as an elongation element of the groundconductor 22, so that the antenna radiation characteristics at a lowfrequency band may be improved.

FIG. 16 illustrates the antenna radiation characteristics of themonopole antenna 32. Thick line “c” represents the characteristics ofthe antenna element 18. Thin line “d” represents the characteristics ofthe antenna element 14 when the housing 4 is closed.

In the case where the housing 4 is closed, the first antenna element 14has a low antenna radiation efficiency and little practicability. Incontrast, the second antenna 18 has a high antenna radiation efficiencywhich is improved by about 20 [dB] even when the housing 4 is closed.

The above embodiment may reduce or prevent the antenna characteristicsfrom being affected by the housing length due to a reduction of size andthickness of the housing and lowered usable frequency band.

When the housing 4 is opened, the housing 6 sets up the dipole antenna28 from the ground conductor (conductor part) 22 and the antenna element18 on the housing part 8 to make the dipole antenna 28 function as afirst antenna element 14. In addition, the second antenna element 18 onthe housing part 8 serves as a monopole antenna 32 when the housing 4 isclosed.

When the housing 4 is opened, the second antenna element 18 is connectedto the ground conductor 22 and operates as a GND elongation element. Asa result, even if the housing part 8 or the housing 4 is shortened, thehousing length may be made appear to be longer with respect to thewireless unit 50 (i.e., the power supply point 24). Thus, degradation ofthe antenna characteristics may be reduced or prevented due to theinfluence of the housing length.

The first antenna element 14, the second antenna element 18, thematching circuits 36, 46, and 48, the ground conductor 22, and thewireless unit 50 are connected to one another through the changeoverswitches 42 and 44. The CPU 54 determines the open or closed state ofthe housing 4 through the open/close sensor 52. The dipole antenna 28 orthe monopole antenna 32 is automatically selected as a desired antennain response to a control signal from the CPU 54. Thus, desired antennacharacteristics may be obtained.

The wireless unit 50 supplies electric power to the first antenna 14when the housing 4 is opened. The matching circuit 36 may be adjusted sothat the resonance point of the first antenna element 14 may correspondto the usable frequency band. The second antenna element 18 is groundedthrough the matching circuit 46 and operates as a GND elongationelement. The matching circuit 46 is adjusted using a constant which maybe most effective for the second antenna element 18 operated as a GNDground at the usable frequency band.

The wireless unit 50 supplies electric power to the second antennaelement 18 when the housing 4 is closed. In this case, the matchingcircuit 48 is adjusted so that the resonance point of the second antennaelement 18 may correspond to the usable frequency band.

When the housing 4 is opened, the CPU 54 determines that the detectionoutput of the open/close sensor 52 represents the open state, and thencontrols the changeover switches 42 and 44. The wireless unit 50 isconnected to the first antenna element 14 through the matching circuit36 and to the ground conductor 22 and the second antenna element 18through the matching circuit 46.

When the housing 4 is closed, the CPU 54 determines that the detectionoutput of the open/close sensor 52 represents the closed state, and thencontrols the changeover switches 42 and 44. At this time, the wirelessunit 50 is connected to the second antenna element 18.

In this embodiment, the matching circuit 46 is constructed of a parallelL, the matching circuit 48 is constructed of a serial L and an LCparallel circuit. Here, L represents an inductance and C represents acapacitance.

The power supply line 26 is integrally formed with the signal line ofthe flexible substrate 39 passing through the hinge 10. The protrudingportions of the flexible substrate 39 are connected to the respectivecircuit boards 12 and 16. That is, the strong connection structurecontributes to the antenna characteristics.

When the cell phone 34 is opened, the influence of the housing length onthe antenna characteristics may be reduced or prevented by the housinglength due to a reduction of size and thickness of the housing and lowerusable frequency band.

The antenna is switched to the second antenna element 18 and the antennaradiation efficiency is improved about 20 [dB] as illustrated in FIG. 16when the cell phone 34 is closed.

As described above, the dipole antenna provided with the antenna elementon the second housing is formed when the housing is in the open stateand the monopole antenna is formed using the antenna element on thesecond housing. Thus, degradation of the antenna characteristics may bereduced or prevented.

When the housing is opened, the second antenna element is connected tothe conductor part of the second housing to extend the antenna length.Thus, degradation of the antenna characteristics may be reduced orprevented.

Since the monopole antenna is constructed of the antenna element on thesecond housing part, degradation of the antenna characteristics may bereduced or prevented.

Third Embodiment

According to a third embodiment, a portable apparatus is designed sothat a power supply unit is simplified and changeover switches areunified. The third embodiment will be described with reference to FIGS.17 to 21. FIG. 17 is a diagram illustrating an example configuration ofan antenna when a cell phone according to the third embodiment is in anopen state. FIG. 18 is a diagram illustrating an example configurationof a dipole antenna. FIG. 19 is a diagram illustrating an exampleconfiguration of a monopole antenna. FIG. 20 is a diagram illustratingan example antenna-switching circuit when the cell phone is in the openstate. FIG. 21 is a diagram illustrating an example antenna-switchingcircuit when the cell phone is in a closed state. In FIGS. 17 to 21, thesame reference numerals denote substantially the same structuralcomponents as those illustrated in FIGS. 3, 7, and 8.

As illustrated in FIG. 17, the cell phone 34 of this embodiment useswiring in the flexible substrate 39 as a part of a power supply line26A. In addition, the aforementioned changeover switches 42 and 44 areunified as a changeover switch 43. In this embodiment, matching circuits36, 46, and 48 are simplified in these figures. Since other structuralcomponents are substantially the same as those of the second embodiment,the same reference numerals will be provided and their descriptions willbe omitted.

Even in this configuration, a dipole antenna 28 is set up when a housing4 is opened as illustrated in FIG. 18 and FIG. 20 and a monopole antenna32 is set up when the housing is closed as shown in FIG. 19 and FIG. 21.

When an open/close sensor 52 detects the open state of the housing 4, awireless unit 50 is connected to a first antenna element 14 through acontact point 431 of the changeover switch 43 and a matching circuit 36,and also connected to a second antenna element 18 through a contactpoint 432 of the changeover switch 43, a matching circuit 46, and aground conductor 22. Therefore, the dipole antenna 28 described above isformed and connected to the wireless unit 50.

When the open/close sensor 52 detects the closed state of the housing 4,the wireless unit 50 is connected to the second antenna element 18through the contact point 432 of the changeover switch 43, the matchingcircuit 48, and the contact point 431 of the changeover switch 42.Therefore, the monopole antenna 32 described above is formed andconnected to the wireless unit 50.

Fourth Embodiment

According to a fourth embodiment, a portable apparatus has theconfiguration of a television (TV) receiver circuit.

The fourth embodiment will be described with reference to FIGS. 22 to24. FIG. 22 is a figure showing a TV receiver circuit exampleconfiguration according to the fourth embodiment. FIG. 23 is a diagramillustrating an example configuration of a dipole antenna which is setup when a cell phone is in an open state. FIG. 24 is a diagramillustrating an example configuration of a monopole antenna which is setup when the cell phone is in a closed state. In each of FIG. 23 and FIG.24, the same reference numerals denote substantially the same structuralcomponents as those illustrated in FIG. 3.

The TV receiver circuit 62 of this embodiment includes a TV receivermodule 64 which is connected to the aforementioned antenna-switchingcircuit 58. The TV receiver module 64 includes a high-frequencyamplifying circuit, a tuning circuit, a demodulating circuit, and so onand is configured to be able to reproduce pictures and sounds of TVbroadcasts.

In this configuration, changeover switches 42 and 44 respectively becomethe states illustrated in the figure when the housing 4 of a cell phone34 is in an open state. In this case, the TV receiver module 64 isconnected to a dipole antenna 28 which is constructed of an antennaelement 14, a ground conductor 22, and an antenna element 18. Thisdipole antenna 28 receives TV broadcasts.

Furthermore, the changeover switches 42 and 44 are in the statesrepresented by dashed lines, respectively, when the housing 4 is in aclosed state. In this case, the TV receiver module 64 is connected tothe antenna element 18 through a matching circuit 48 and the changeoverswitches 42 and 44. In other words, the TV receiver module 64 isconnected to the monopole antenna 32, so that TV broadcasts may bereceived through the monopole antenna 43.

The TV receiver module 64 may receive TV broadcasts through either ofthe antennas 28 and 32. In the case where the housing 4 is in the openstate, the antenna element 18 is provided as a part of the dipoleantenna 28 and serves as an elongation element of a ground conductor 22of the antenna element 18. Therefore, improvements in radiationcharacteristics and TV receiver sensitivity of the antenna may beattained. In this case, as illustrated in FIG. 23, emission current I₁flows through the housing part 6 of the dipole antenna 28 and emissioncurrent I₂ flows through the housing part 8 of the dipole antenna 28when the housing 4 of the cell phone 34 is opened. Therefore, since theemission currents I₁ and I₂ are in phase with each other and the antennaelement 18 serves as an elongation element, the radiationcharacteristics of the antenna may be enhanced.

When the housing 4 is closed, as illustrated in FIG. 24, the emissioncurrents I₁ and I₂ flowing through the housing parts 6 and 8 are inopposite phase and cancel each other out. The antenna element 18 isconnected as a monopole antenna 32 to the TV receiver module 64 andreceives the supply of electric power. As a result, even if the housing4 is closed, TV broadcasts may be received by the monopole antenna 32with similar quality as the dipole antenna 28.

In this embodiment and the aforementioned embodiments, the maximumradiation efficiency may be obtained by adjusting the length of theantenna element 18 and performing matching adjustment of matchingcircuits 36, 46, and 48.

According to the above configuration, the addition of the antennaelement 18 may result in desired antenna radiation efficiency forreceiving broadcasts, such as TV broadcasts, irrespective of the openingor closing of the housing 4. Therefore, broadcast receptioncharacteristics may be improved.

Other Embodiments

In the aforementioned embodiments, the portable apparatus 2 and the cellphone 34 have been described for illustrative purposes, but are notlimited thereto. For example, the aforementioned embodiments may beapplied to a personal digital assistant (PDA), a personal computer, or aTV receiver, which are capable of receiving broadcasts.

Radiation efficiency has been described for the purpose of describingthe antenna characteristics. Likewise, the dipole antenna and themonopole antenna of the present disclosure have increased antenna gainsbecause each of them is provided with the antenna element 18.

Comparative Example

The antenna characteristics of an openable/closable portable apparatusas a comparative example will be described.

FIG. 25 and FIG. 26 are referred to for the comparative example. FIG. 25illustrates a dipole antenna which is set up in a cell phone in an openstate. FIG. 26 illustrates an antenna which is set up in a cell phone ina closed state.

The cell phone 200 of the comparative example includes housing parts 206and 208 as an openable/closable housing 204.

When the housing 204 is opened, as illustrated in FIG. 25, the housingparts 206 and 208 serve as antenna elements, respectively, and a powersupply point 224 is provided in a dipole antenna 228. The dipole antenna228 includes a circuit board 212 on the housing part 206 and a circuitboard 216 on the housing part 208, which serve as antenna elements,respectively. In other words, emission currents I₁ and I₂ in phase flowthrough the circuit boards 212 and 216, which serve as antenna elements,respectively. In this dipole antenna 228, the length of the housing isshort with respect to usable wavelengths when the cell phone 200 isreduced in size or a usable frequency band is lowered. As a result, adecrease in antenna performance may occur.

However, as illustrated in FIG. 26, when the housing 204 is closed, theemission current I₁ flowing through the circuit board 212 and theemission current I₂ flowing through the circuit board 216 become out ofphase with each other, so that they may have difficulty functioning asantennas or a decrease in antenna characteristics may occur.

In this cell phone 200, if the housing 204 is downsized and the lengththereof is shortened, a sufficient antenna length may not be obtainedeasily. If an extension board is placed on the housing part 206 or thehousing part 208 and connected to the circuit board via a connectionmember to obtain a sufficient antenna length, an additional space may bedesired for the extension board. This configuration prevents the cellphone 200 from being reduced in size and thickness.

According to the aforementioned embodiments, the dipole antenna and themonopole antenna may realize excellent antenna characteristics without areduction in size or impairing flatness of the housing. Furthermore, thedipole antenna and the monopole antenna may be switched from each otherby opening or closing the housing. In the dipole antenna, the antennaelement 18 is added to the ground conductor 22 to complement the lengthof the conductor, thereby reducing or preventing degradation of theantenna characteristics by a reduction in the size of the housing.

All examples and conditional language recited herein are intended forpedagogical purposes to aid the reader in understanding the principlesof the invention and the concepts contributed by the inventor tofurthering the art, and are to be construed as being without limitationto such specifically recited examples and conditions. Although theembodiments of the present invention have been described in detail, itshould be understood that the various changes, substitutions, andalterations could be made hereto without departing from the spirit andscope of the invention.

1. A wireless communication apparatus, comprising: a first housing; asecond housing which is openably and closably connected to the firsthousing through a hinge; a first conductor part which is arranged on thefirst housing; a second conductor and an antenna element, which arearranged on the second housing; and an antenna switching part that makesthe first conductor part, the second conductor part, and the antennaelement serve as a dipole antenna when the first housing and the secondhousing are in an open state, and makes the antenna element serve as amonopole antenna when the first housing and the second housing are in aclosed state.
 2. The wireless communication apparatus according to claim1, further comprising: an opening/closing detection unit to detectopening and closing of the first housing and the second housing; and acontrol unit to control the antenna switching part in response to thedetection by the opening/closing detection unit.
 3. The wirelesscommunication apparatus according to claim 1, further comprising: apower supply unit; a first matching circuit which is placed between thefirst conductor part and the power supply unit; and a second matchingcircuit which is placed between the power supply unit and the antennaelement.
 4. The wireless communication apparatus according to claim 1,wherein the antenna element is connected to the second conductor throughthe third matching circuit when the first housing and the second housingare opened.